Evaluate the Function for the Indicated Value, Then Simplify $f ( x ) = x ^ { 2 } + 5 x$

Multiple Choice

Evaluate the function for the indicated value, then simplify.
- $f ( x ) = x ^ { 2 } + 5 x$ ; find $f ( a + 1 )$ , then simplify as much as possible.

A) $a ^ { 2 } + 7 a + 6$
B) $a ^ { 2 } + 7 a + 7$
C) $a ^ { 2 } + 3 a + 2$
D) $a ^ { 2 } + 3 a + 6$